Everyone worries about behaviour management. It takes time to develop the range of strategies to work the room really well. Until then use the behaviour policy as your starting point. You'll pick up the small preventative and redirecting things as you go.
Don't take things personally. Some lessons will be shit. Some days you'll feel really rubbish. Some days it can feel like a lesson you slaved over was ruined by a student. Some professional criticism may feel personal but it's there to help you learn. All of that is normal. Talk to your mentor. We will have seen it all before.
Avoid trainee group chats or at the very least know when to eye roll to yourself. There is nothing more annoying than show offs pretending that their mentor loves them and their 3rd ever lesson was almost outstanding, their students love them, they know everything there is to know, their department is falling over themselves to implement their new idea, their classes are doing so well, they've been promised a job by day 8. And equally, avoid feeding the moaning minnies who are always victims, always bitching about placements, always whining about how people don't get them, their school is awful, they're working 78 hours a day because it's worth it for the kids.
Read widely, read blogs, articles, good books.
Batch cooking is really helpful.
Block off time for your hobbies and social time and protect it religiously.